Spa shell



FIG. 1 is a first perspective view of a spa shell showing our new design;

FIG. 2 is a top plan view of a spa shell showing our new design;

FIG. 3 is a side view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is a side view thereof;

FIG. 6 is a side view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 4.

The broken-line disclosure in the views represents portions of the article in which the claimed design is embodied, but which form no part of the claimed design. 

CLAIM The ornamental design for a spa shell, as shown and described. 